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18-Env-A6 Solid Waste Engineering and Management · May 2013

Question 3 of 17: Reducing Costs Beyond Collection

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

Notes on this paper

National Examination, May 2013 — 04-Env-A6 / 18-Env-A6, Solid Waste Engineering and Management. 3 hours duration, closed book, one letter-sized aid sheet permitted. All 17 questions constitute a complete paper (100 marks total).

Reference texts: Tchobanoglous, Theisen & Vigil, Integrated Solid Waste Management: Engineering Principles and Management Issues; Vesilind, Worrell & Reinhart, Solid Waste Engineering; Davis & Cornwell, Introduction to Environmental Engineering (6th ed.); CCME, Guidance Document on Landfill Gas Management.

Check: several questions on this paper (Q1, Q13, Q14, Q17) supply an incomplete data set and explicitly invite the candidate to "make and state" assumptions. Every assumed value below is called out where it is introduced and is chosen from standard solid-waste-engineering practice; the governing METHOD, not the specific assumed number, is what the exam is testing.

Question 3: Reducing Costs Beyond Collection (4 marks)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

Since collection dominates the budget, cost reduction strategies focus on shrinking either the tonnage collected or the effort per tonne: (1) source reduction and diversion — recycling and composting programs remove material from the collected waste stream before a truck ever visits it; (2) collection route and schedule optimization — GIS-based routing, reduced frequency (e.g., weekly instead of twice-weekly) or alternating-week recycling/refuse pickup cuts truck-hours directly; (3) larger vehicle/container capacity and compaction — bigger packer trucks or automated side-loaders reduce the number of trips needed to clear the same tonnage; and (4) regional consolidation via transfer stations — shifting from many short direct hauls to a transfer-and-linehaul system once distances to disposal grow, cutting collection-vehicle haul time.